JPH10263658A - Flatness control method of rolled stock in hot finishing mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable high precise flatness control even after coiling a rolled stock onto a coiler. SOLUTION: In the case of coiling the rolled stock S rolled with a hot finishing mill 1 with the coiler 5, the degree of flatness is measured just before coiling the rolled stock S onto the coiler 5 to operate the difference in elongation percentage and the degree of flatness is measured just after coiling onto the coiler 5 to operate the difference in elongation percentage with a flatness gage 6 arranged in the outlet side of the finishing mill 1, the difference in elongatiorn percentage of the rolled stock S obtained after coiling onto the coiler 5 is corrected using the ratio of these differences in elongation percentage to control the work roll bender 3 of the finishing mill 1, whereby flatness control having excellent precision is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for controlling flatness of a rolled material in a hot finishing mill.

[0002]

2. Description of the Related Art Conventionally, as a quality of a rolled material rolled by a tandem rolling mill (hereinafter simply referred to as a rolling mill), a material having good flatness is required. As a method of controlling the flatness, a method of installing a flatness meter on the exit side of a rolling mill and operating a bender of a final stand of the rolling mill based on the measured value is generally used.

[0003] Various types of flatness meters have been developed (for example, see Theory and Practice of Sheet Rolling, edited by The Iron and Steel Institute of Japan, pages 265 to 270, (1984)). In this case, it is general to calculate the difference in elongation percentage in the width direction using the tension distribution in the width direction of the rolled material. On the other hand, in hot rolling, a method of measuring a height variation in a longitudinal direction at each point in a width direction of a rolled material and calculating flatness is generally used.

[0004]

However, in the flatness gauge generally used in the above-mentioned hot rolling, tension is not generated in the rolled material before the rolled material is wound around the coiler arranged on the exit side of the rolling mill. Therefore, it is possible to measure the flatness accurately, but after the rolled material is wound around the coiler, tension is generated in the rolled material, and the shape is partially latent, so that accurate measurement cannot be performed. Therefore, there is a disadvantage that bending control cannot be performed with high accuracy.

An object of the present invention is to provide a method for controlling the flatness of a rolled material in a hot finish rolling mill which has solved the problems of the prior art as described above.

[0006]

SUMMARY OF THE INVENTION According to the present invention, when a rolled material rolled by a hot finish rolling mill is wound up by a coiler, a flatness measured by a flatness meter installed on an output side of the rolling mill is measured. A method of controlling the flatness of a rolled material using the method, wherein the flatness meter measures the flatness just before the rolled material is wound around the coiler to calculate an elongation difference, and winds around the coiler. Calculating the elongation difference by measuring immediately after the work roll of the rolling mill by correcting the elongation difference of the rolled material obtained after being wound around the coiler using the ratio of these elongation differences. And v. Controlling the vendor. 2. A method for controlling flatness of a rolled material in a hot finishing mill, comprising the steps of:

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an embodiment of the present invention. In this figure, 1
Is a hot finishing rolling mill composed of, for example, seven stands, and a work roll bender 3 is arranged on the final stand 2. 4
Is a runout table composed of a plurality of rollers. 5
Is the No. 1 coiler 5a and No. 2 coiler 5b
The rolled material S composed of a base and rolled by the hot finishing mill 1 is wound up alternately.

Reference numeral 6 denotes a flatness meter, which is mounted on the runout table 4 on the exit side of the hot finishing mill 1. Reference numeral 7 denotes a coiler tracking signal generator such as an HMD.
It is mounted on the top of No. 1 coiler 5a and No. 2 coiler 5b. Reference numeral 8 denotes a flatness calculation control device which inputs a measurement signal of the flatness meter 6 and a tracking signal from the coiler tracking signal generation device 7 to calculate flatness, and outputs the work roll bender 3 via a bender control device 9. Control. 10 is a setup calculator.

Here, the content of the calculation procedure in the flatness calculation control device 8 will be described. Now, the average value of the elongation percentage at a predetermined position (for example, 100 mm) from the end of the rolled material S on the operator side and the drive side Is ε _E and the elongation percentage at the center in the width direction of the rolled material S is ε _C , and the flatness signal measured by the flatness meter 6 is represented by the following elongation difference Δε:
It is expressed by equation (1).

[0010] _{Δε = ε E -ε C .................. (} 1) Thus, first, the flatness control processor 8 this elongation difference Δ
In response to ε, the bender operation amount ΔF before the rolled material S is wound around the coiler 5 is calculated by the following equation (2). ΔF = {1 / (δε / δF)} · K _P · {1 + 1 / (T _I · s)} · (Δε−Δε ₀ ) where δε / δF is a work roll. The coefficient of influence on the difference in elongation from the vendor 3 is a predetermined rolling model formula (for example,
Edited by The Iron and Steel Institute of Japan: “Theory and Practice of Sheet Rolling” P308-313, (1
984)). K _P is a proportional gain, T _I is an integration time constant, and these are generally called PI gains.
Δε ₀ is a target value of elongation difference, which is a value determined from the product specifications of the rolled material S.

Next, the bender operation amount ΔF after the rolled material S is wound around the coiler 5 is calculated by the following equation (3). ΔF = {1 / (δε / δF)} · K _P · {1 + 1 / (T _I · s)} · ｛(Δε ₁₀ / Δε ₂₀ ) · Δε−Δε ₀ … ……………… (3) in, [Delta] [epsilon] ₁₀ growth rate difference of the rolling material rolled material S was measured by the flatness meter 6 just before wound around the coiler 5, [Delta] [epsilon] ₂₀ is measured by a flatness meter 6 immediately after the rolled material S is wound around the coiler 5 This is the difference in elongation percentage of the rolled material.

The operation of the present invention will be described below. It is assumed that the rolled material S rolled by the hot finish rolling mill 1 is wound through a run-out table 4 to, for example, a No. 1 coiler 5a. Until the rolled material S is wound around the No. 1 coiler 5a, the flatness is measured by the flatness meter 6 and input to the flatness calculation control device 8. ) Is used to calculate the vendor operation amount ΔF before winding around the coiler 5;
Output to the vendor control device 9. The vendor controller 9 controls the bending pressure of the work roll bender 3 based on this. In addition, the influence coefficient δε / δF, the proportional gain K _P , the integration time constant T _I , the elongation difference target value Δε in the equation (2)
_“0” is transmitted to the flatness calculation control device 8 in advance as a setting calculation result in the setup computer 10 and set.

On the other hand, the coiler tracking signal generator 7
Monitors the tracking state of the rolled material S,
A coiler-on signal is transmitted to the flatness calculation controller 8 when the coiler is wound around the No. 1 coiler 5a. At this timing, the flatness calculation controller 8 determines that the rolled material S is the No. 1 coiler 5
stores the elongation difference [Delta] [epsilon] ₂₀ of the strip immediately after wound around the No. 1 coiler 5a and elongation difference [Delta] [epsilon] ₁₀ of the strip as measured by the flatness meter 6 just before wound on a, No. 1 coiler 5a
After the winding, the vendor operation amount ΔF is calculated using the above equation (3).
Is calculated and output to the bender control device 9 to control the bending pressure of the work roll bender 3.

Incidentally, the method of the present invention was applied when a rolled material having a sheet thickness of 2.3 mm and a sheet width of 1200 mm was rolled using a 7-stand hot finishing mill. A laser distance meter type was used as the flatness meter. FIG. 2 shows the flatness (%) measured by the contact flatness meter in the next step. It can be seen that the flatness accuracy after winding the coiler is more than doubled in the method of the present invention as compared with the conventional method.

[0015]

As described above, according to the present invention,
By a flatness meter, the flatness is measured just before winding around the coiler, and the elongation difference is calculated by measuring the flatness, and immediately after winding around the coiler, the elongation difference is calculated. Controlling the work roll bender of the rolling mill by correcting the difference in elongation of the rolled material obtained after being wound around the coiler by using the ratio of the difference in elongation. High precision flatness control is possible even after winding.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing transition of flatness.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hot finishing rolling mill 2 Final stand 3 Work roll bender 4 Run out table 5 Coirer 5a No. 1 Coiler 5b No. 2 Coirer 6 Flatness meter 7 Coiler tracking signal generator 8 Flatness calculation control device 9 Vendor control device 10 Setup calculator S Rolled material

Claims (1)

[Claims] When a rolled material rolled by a hot finish rolling mill is taken up by a coiler, the flatness of the rolled material is measured by using a flatness meter measured by a flatness meter installed on an outlet side of the rolling mill. A method for controlling the flatness meter, while calculating the difference in elongation by measuring the flatness just before the rolled material is wound around the coiler,
Measuring the elongation difference by measuring immediately after winding on the coiler; and correcting the elongation difference of the rolled material obtained after winding on the coiler using the ratio of these elongation differences to perform the rolling. Controlling the work roll bender of the mill. 2. A method for controlling flatness of a rolled material in a hot finishing mill.